Using AWS types in AwsProperties instead of Strings

Author: szlta

aws/src/main/java/org/apache/iceberg/aws/AwsProperties.java

@@ -211,13 +211,13 @@ public class AwsProperties implements Serializable {
   /** Encryption algorithm used to encrypt/decrypt master table keys */
   public static final String KMS_ENCRYPTION_ALGORITHM_SPEC = "kms.encryption-algorithm-spec";
 
-  public static final String KMS_ENCRYPTION_ALGORITHM_SPEC_DEFAULT =
-      EncryptionAlgorithmSpec.SYMMETRIC_DEFAULT.toString();
+  public static final EncryptionAlgorithmSpec KMS_ENCRYPTION_ALGORITHM_SPEC_DEFAULT =
+      EncryptionAlgorithmSpec.SYMMETRIC_DEFAULT;
 
   /** Length of data key generated by KMS */
   public static final String KMS_DATA_KEY_SPEC = "kms.data-key-spec";
 
-  public static final String KMS_DATA_KEY_SPEC_DEFAULT = DataKeySpec.AES_256.toString();
+  public static final DataKeySpec KMS_DATA_KEY_SPEC_DEFAULT = DataKeySpec.AES_256;
 
   private final Set<software.amazon.awssdk.services.sts.model.Tag> stsClientAssumeRoleTags;
 
@@ -243,8 +243,8 @@ public class AwsProperties implements Serializable {
   private String restAccessKeyId;
   private String restSecretAccessKey;
   private String restSessionToken;
-  private String kmsEncryptionAlgorithmSpec;
-  private String kmsDataKeySpec;
+  private EncryptionAlgorithmSpec kmsEncryptionAlgorithmSpec;
+  private DataKeySpec kmsDataKeySpec;
 
   public AwsProperties() {
     this.stsClientAssumeRoleTags = Sets.newHashSet();
@@ -313,9 +313,12 @@ public AwsProperties(Map<String, String> properties) {
     this.restSessionToken = properties.get(REST_SESSION_TOKEN);
 
     this.kmsEncryptionAlgorithmSpec =
-        properties.getOrDefault(
-            KMS_ENCRYPTION_ALGORITHM_SPEC, KMS_ENCRYPTION_ALGORITHM_SPEC_DEFAULT);
-    this.kmsDataKeySpec = properties.getOrDefault(KMS_DATA_KEY_SPEC, KMS_DATA_KEY_SPEC_DEFAULT);
+        EncryptionAlgorithmSpec.fromValue(
+            properties.getOrDefault(
+                KMS_ENCRYPTION_ALGORITHM_SPEC, KMS_ENCRYPTION_ALGORITHM_SPEC_DEFAULT.toString()));
+    this.kmsDataKeySpec =
+        DataKeySpec.fromValue(
+            properties.getOrDefault(KMS_DATA_KEY_SPEC, KMS_DATA_KEY_SPEC_DEFAULT.toString()));
   }
 
   public Set<software.amazon.awssdk.services.sts.model.Tag> stsClientAssumeRoleTags() {
@@ -426,11 +429,11 @@ public AwsCredentialsProvider restCredentialsProvider() {
   }
 
   public EncryptionAlgorithmSpec kmsEncryptionAlgorithmSpec() {
-    return EncryptionAlgorithmSpec.fromValue(this.kmsEncryptionAlgorithmSpec);
+    return this.kmsEncryptionAlgorithmSpec;
   }
 
   public DataKeySpec kmsDataKeySpec() {
-    return DataKeySpec.fromValue(this.kmsDataKeySpec);
+    return this.kmsDataKeySpec;
   }
 
   private Set<software.amazon.awssdk.services.sts.model.Tag> toStsTags(